a)25-(25-x)=12+(42-65) b)5+/x+3/=9
c)31-(17+x)=18 d)x-(-25+x)=13-x
e)15-(30+x)=x-(27-/-8/)
f)(12x-4^3).8^3=4.8^4
g)[119-(3^3-10)].x=2448
h)[(10-x).2+51]:3-2=3
a)25-(25-x)=12+(42-65) b)5
By Madelyn
`a)25-(25-x)=12+(42-65)`
`→25-25+x=12-23`
`→x=-11`
Vậy `x=-11`
`b)5+|x+3|=9`
`→|x+3|=9-5`
`→|x+3|=4`
`→` \(\left[ \begin{array}{l}x+3=4\\x+3=-4\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=1\\x=-7\end{array} \right.\)
Vậy `x∈{1;-7}`
`c)31-(17+x)=18`
`→31-17-x=18`
`→14-x=18`
`→x=14-18`
`→x=-4`
Vậy `x=-4`
`d)x-(-25+x)=13-x`
`→x+25-x=13-x`
`→13-x=25`
`→x=13-25`
`→x=-12`
Vậy `x=-12`
`e)15-(30+x)=x-(27-|-8|)`
`→15-30-x=x-19`
`→x-19=-15-x`
`→x+x=-15+19`
`→2x=4`
`→x=2`
Vậy `x=2`
`f)(12x-4^3).8^3=4.8^4`
`→12x-4^3=4.8`
`→12x-64=32`
`→12x=96`
`→x=96:12`
`→x=8`
Vậy `x=8`
`g)[119-(3^3-10)].x=2448`
`→(119-17)x=2448`
`→102x=2448`
`→x=2448:102`
`→x=24`
Vậy `x=24`
`h)[(10-x).2+51]:3-2=3`
`→[(10-x).2+51]:3=5`
`→(10-x).2+51=15`
`→(10-x).2=-36`
`→10-x=-18`
`→x=10-(-18)`
`→x=28`
Vậy `x=28`
Đáp án:
Giải thích các bước giải:
a)25 – (25 – x)=12 + (42 – 65)
25 – 25 + x=12 + 42 – 65
x=(-11)
Vậy x=-11
b)5 + |x + 3|=9
|x + 3|=9 – 5
|x + 3|=4
TH1: x + 3=4⇒x=1
TH1: x +3=(-4)⇒x=(-7)
Vậy x∈{1;-7}
c)31 – (17 + x)=18
31 – 17 – x=18
14 – x=18
x=14 – 18
x=(-4)
Vậy x=-4
d)x – (-25 + x)=13 – x
x + 25 – x=13 – x
25 =13 – x
13 – x=25
x=13 – 25
x=(-12)
Vậy x=(-12)
e)15 – (30 + x)=x – (27 – |-8|)
15 – 30 – x=x – 27 + 8
– x – x=- 27 + 8 – 15 + 30
– 2x=-4
x=2
Vậy x=2
f)(12x – 4³).8³=4.$8^{4}$
(12x – 64).512=4.4096
6144x – 32768=16384
6144x =16384 + 32768
6144x =49152
x =8
Vậy x=8
g)[119 – (3³ – 10)].x=2448
[119 – (27 – 10)].x=2448
[119 – 27 + 10].x=2448
102.x=2448
x=24
Vậy x=24
h)[(10 – x).2 + 51] : 3 – 2=3
[20 – 2x + 51] : 3 =5
71 – 2x =15
2x =71 – 15
2x =56
x =28
Vậy x=28